With each phase of clinical trials, our knowledge about a medicine and its safety and effectiveness grows.
In Phase 1 trials, researchers test a new drug or treatment in a small group of people (20-80) for the first time to evaluate its safety, determine a safe dosage range, and identify side effects.
In Phase 2 trials, the study drug or treatment is given to a larger group of people (100-300) to see if it is effective and to further evaluate its safety.
In Phase 3 trials, the study drug or treatment is given to large groups of people (1,000-3,000) to confirm its effectiveness, monitor side effects, compare it to commonly used treatments, and collect information that will allow the drug or treatment to be used safely.
In Phase 4 trials, studies look at real-world experience in the general population over a long time and provide additional information on the drug’s risks, benefits, and optimal use.